1. Field of the Invention
This invention discloses a recombinant protein, especially a recombinant protein containing the biologically active peptide, a pharmaceutical composition containing the same and a method of biosynthesizing thereof.
2. Description of the Related Art
Among the peptide, amino acid and protein, the molecular weight of peptide is between amino acid and protein Amino acid is the basic unit with least molecule weight in the protein, and protein is largest molecule assembled by one or multiple peptide chains. The peptide chain is accomplished by formation of the peptide bond from two or more amino acids with loss of the water molecule. After the peptide chains formation, these multiple peptide chains further assemble into protein through dehydroxylation. On the other hand, protease mediated proteolysis breakdowns the protein into multiple peptide chains with molecular size in nanometer scale. Therefore, peptide in nanometer scale is tent to be absorbed by intestines, stomach, blood vessels and skin.
Peptides include the nutritional peptides and functional peptides according to their functions. Nutritional peptides are the source of amino acids for animals and human beings. Functional peptides, the bioactive peptides, exhibit specific physiological activity in animals and human beings and have wide application.
So far, production of the bioactive peptides is by using protease-mediated proteolysis from edible protein or directly synthesizing by ligation of amino acids when the bioactive peptide comprising less than five amino acid residues.
However, these methods of bioactive peptides have low yield and elevate the manufacturing cost, therefore limit the peptide synthesis in industrial scale. Due to the concern of cost and price, the concentration of bioactive peptides applied in drugs, health foods and cosmetics rarely reach the optimized concentration. So the bioactive peptides applied in these products are unable to exhibit claimed function for preventing or curing the targeted diseases while consumers take these products.
Actually, these applied bioactive peptides are functional in the experiment of selection or animal tests, but fail to reveal the same in commercial products for consumers. One reason of functional deficiency lies on low concentration of bioactive peptides in the commercial product. The other reason is the orally taken bioactive peptides contained in products are destroyed by various proteases in digestion tract.
Previous patent, Taiwan Patent No. I315341, filed by the applicant had disclosed a method for biosynthesizing the VVVP peptide-protein producing with edible bacterium utilizing single copy insertion of said peptide into each replacement region within the carrier protein α-amylase. But the expression vector comprises six replacement regions and each of them is inserted with single copy of bioactive peptide and the carrier protein is purified from Ni-NTA purification system. Therefore, the ratio of the bioactive peptides in the protein product is only 3% which is too low for commercial production and the protein product may contain heavy metal nick which is toxic for human body.
Collectively, the improvement of producing yield of the bioactive peptides and increasing of the bioactive peptide concentration in final protein product come to be a critical issue in the field of peptides production.